This invention relates, in general, to recording test results and location of a die after a wafer probe test, and more particularly, to a method for recording test results and location of a die on a wafer which avoids marking the wafer with ink.
Maintaining an electronic data base of wafer map information involves unacceptable risks of loss of data and misidentified wafers. It is common practice in the semiconductor industry to place an ink dot on rejected die of a wafer at probe test. At a die bond station these dots are detected with an automatic electronic vision system. Using an ink dot to indicate rejected die causes many problems. The inker requires set up time as well as continuous maintenance. There is difficulty in controlling the consistency of the ink used. Occasionally the ink will splatter and contaminate neighboring good die. It is not uncommon for the ink dot to fall off or for the ink dot to be difficult to be recognized on certain die by the automatic electronic vision system. Failure to detect a failed die results in the die bonder processing a bad die. Also, the semiconductor factory of the future must become inkless to allow multiple categorization of good die (grade A, grade B, etc.) on a semiconductor wafer. It should therefore be appreciated that it would be desirable to provide a method that overcomes the above indicated deficiencies.
Accordingly, it is an object of the present invention to eliminate applying ink to a die in order to indicate its tests results.
Another object of the present invention is to apply state of the art recording and scanning techniques to record test results of a die.